Not applicable.
Not applicable.
This invention relates to elliptical expansion plugs that are designed to seal elliptical holes in castings.
Circular expansion plugs have been used for many years to seal circular openings in castings. A common application for expansion plugs is the use of a circular expansion plug to seal a circular freeze plug opening in an automobile engine block. While a number of designs for expansion plugs have been patented, such as U.S. Pat. No. 4,750,457 by Bonutti and U.S. Pat. No. 4,494,670 by Barone, these patents identify the use of circular expansion plugs. This is because past practice in making metal castings dictated that openings within the castings be circular. Following an assembly or machining operation, the circular opening in the casting is then sealed with a circular expansion plug.
Circular expansion plugs are typically produced with a single radius. By maintaining a constant radius the expansion plug""s sealing edges will be in the same plane. To install a circular expansion plug, the expansion plug is normally set onto a counter bore in the circular hole in the casting and then flattened. Flattening the concave circular expansion plug forces the outer edges of the plug to seal against the inside of the circular hole.
The expansion plug openings in the past have virtually always been round in shape due to the ease in machining a round hole. If a passage that is 1xe2x80x3 tall and 2xe2x80x3 wide needs to be sealed, a circular plug having a diameter of 2xe2x80x3 or more must be used despite the fact the opening to be sealed only requires a plug about 1xe2x80x3 tall. Thus, due to past limitations in machining castings, the opening in the casting had to be round and therefore, the plug had to be of a size to fit the largest dimension of the opening in the casting.
However, due to the dimensional limitations of some casting applications and the need for special internal features in some castings, a circular hole may be either too large or will interfere with the various features of the casting. By utilizing an elliptical hole in conjunction with an elliptical expansion plug, the sealing area can be extended into a rectangular section versus a square or round section, as required with circular expansion plugs. As with a concave circular expansion plug, flattening a concave elliptical expansion plug also forces the outer edge of the plug to seal against the elliptical counter bored hole.
With the advent of Computer-Numerically Controlled (xe2x80x9cCNCxe2x80x9d) machining, almost any hole shape can be machined into a casting, including elliptical shaped holes. This advent of modern machining practices requires that new shapes and styles of plugs be designed to fit these new hole shapes. In the previous example, the 1xe2x80x3 tall by 2xe2x80x3 wide passage in the casting can now be matched with an elliptical hole machined or cast into the casting, the machining being accomplished by a computer controlled machining tool. To properly plug this elliptical hole, a properly designed elliptical expansion plug must now be used. In this example, an elliptical plug would be approximately 1.750xe2x80x3 tall and 2.500xe2x80x3 wide would be used to plug the elliptical hole in the machined casting.
The object of this invention is to provide a means to seal an elliptical opening formed or machined into a casting. In accordance with this objective, this invention contemplates an elliptical expansion plug for sealing elliptical openings within a casting. The plug includes an elliptical shape having a major axis and a minor axis, a concave surface is produced by varying the radii between the minor and major diameters so as to maintain the sealing edge in a single plane. For the sealing edge on a circular expansion plug to work properly, when the plug is flattened (installed), the forces around the circumference needs to be the same. The same holds true with the elliptical expansion plug. Since the radius of the curvature varies from the major axis to the minor axis, the minor axis of the hole is a little bit bigger with respect to the expansion plug than the major axis of the hole, with respect to the expansion plug, thus equal sealing force is achieved.
The present invention resides in a concave elliptical expansion plug. The shape of the concaved elliptical expansion plug is determined by matching the major axis and minor axis of the elliptical expansion plug with the elliptical shape of the elliptical opening to be plugged within the casting. The essence of the invention, though, is that by expanding the casting into the form of the elliptical feature as shown in the drawings, the casting can become a more universal style of casting that may be used for many different styles of fuel dispensing nozzles. For example, with the elliptical plug, the handle casting can be used for the standard type of fuel dispensing nozzle. But in addition, the same type of casting, because of the extended length that it attains for the nozzle, can be used, without further modification, for housing the various components that are used in the automatic shut-off nozzle, and likewise, the same type of casting can be used for a nozzle that incorporates the various features for providing vapor recovery systems, through the nozzle, where that type of fuel dispensing is required by code. Essentially the nozzle casting becomes universal for various types of nozzles that are now currently used in the industry, to construct fuel dispensing nozzles, thereby eliminating the need to have three different types of castings, for fuel dispensing nozzles, that currently prevails in the trade.